On Wed, Aug 07, 2024 at 12:15:33PM +0300, Murthy, Arun R wrote: > > > -----Original Message----- > > From: Deak, Imre <imre.deak@xxxxxxxxx> > > Sent: Tuesday, August 6, 2024 10:11 PM > > To: Murthy, Arun R <arun.r.murthy@xxxxxxxxx> > > Cc: intel-xe@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > Subject: Re: [PATCH] drm/xe/pm: Change HPD to polling on runtime suspend > > > > On Tue, Aug 06, 2024 at 02:25:13PM +0530, Arun R Murthy wrote: > > > HPD is interrupt based and on runtime suspend change it to polling as > > > HPD is not a wakeup event. A worker thread is scheduled for doing this > > > polling and it keeps polling for HPD live status on an internval of 10s. > > > On runtime resume disable polling and fallback to interrupt mechanism. > > > > > > Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> > > > --- > > > drivers/gpu/drm/xe/xe_pm.c | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c > > > index 9f3c14fd9f33..d952b06ebfb4 100644 > > > --- a/drivers/gpu/drm/xe/xe_pm.c > > > +++ b/drivers/gpu/drm/xe/xe_pm.c > > > @@ -22,6 +22,7 @@ > > > #include "xe_pcode.h" > > > #include "xe_trace.h" > > > #include "xe_wa.h" > > > +#include "intel_hotplug.h" > > > > > > /** > > > * DOC: Xe Power Management > > > @@ -378,6 +379,8 @@ int xe_pm_runtime_suspend(struct xe_device *xe) > > > if (err) > > > goto out; > > > } > > > + /* Enable hpd polling on runtime suspend */ > > > + intel_hpd_poll_enable(xe); > > > > > > xe_irq_suspend(xe); > > > > > > @@ -427,6 +430,9 @@ int xe_pm_runtime_resume(struct xe_device *xe) > > > > > > xe_irq_resume(xe); > > > > > > + /* Disable hpd polling on runtime resume */ > > > + intel_hpd_poll_disable(xe); > > > > This should be handled in xe_display_pm_resume() (likewise enabling polling in > > xe_display_pm_suspend()), in fact it's already called there. > > In xe_display_pm_suspend we have drm_kms_helper_poll_disable and it disables > output polling. What I meant is that intel_hpd_poll_disable() is already called in xe_display_pm_resume(), which you would call now twice during runtime resume if d3cold is allowed. drm_kms_helper_poll_disable() in xe_display_pm_suspend() should be called only during system suspend, which is another thing to fix there. > Moreover we don't have the functions defined for enable/disable_hpd > defined in connector_ops which is referenced by > drm_kms_helper_poll_enable/disable. > > What we need is on runtime_suspend the poll work should be > enabled so that hotplug can be detected and can come out of runtime_suspend. > The same poll work is not required on system suspend. All the display related suspend/resume handling is done already in xe_display_pm_suspend()/resume() or in xe_display.c in general, both for runtime and system suspend/resume. The reason for that is to keep the display specific parts separate from the generic/higher-level device suspend/resume handling in xe_pm.c. New display specific things added should keep this separation. > > Also this is missing the xe->info.enable_display check and polling shouldn't be > > enabled when system (vs. runtime) suspending. > Probably HAS_DISPLAY can be added before calling this intel_hpd_poll_enable. > > Thanks and Regards, > Arun R Murthy > -------------------- > > > > Not sure why the display is suspended/resumed only if d3cold is allowed, for > > many of the display s/r steps at least it doesn't make sense to me. > > For now moving the d3cold check within > > xe_display_pm_suspend()/resume() and enabling/disabling polling regardless of > > that flag would be the simplest imo. > > > > > + > > > for_each_gt(gt, xe, id) > > > xe_gt_resume(gt); > > > > > > -- > > > 2.25.1 > > >
